Athletes, especially long distance runners, and people who spend a lot of time on their feet (i.e., doctors, nurses, factory workers, and sales persons, to name a few) often get sore feet or damage their feet to the point of developing a debilitating condition such as plantar fasciitis. Plantar fasciitis is a condition in which the flat band of tissue (ligament) connecting the heal bone to the toes is weak, irritated, and/or swollen. Commercially available foot rollers purport to help relieve foot discomfort associated with plantar fasciitis. Conventional foot rollers may nominally be categorized into three groups: 1) rigid and non-rigid shafts with rolling members, 2) cylindrical shapes with concavity and/or external features, and 3) spherical semi-deformable devices.
The first group of foot rollers typically has a shaft passing through semi-deformable spherical, cylindrical or barrel shaped rolling elements that rotate around the axis of the shaft (e.g., an axle). Several rows of such rollers may be incorporated into a single device. Although the rolling elements may rotate about the axis of the shaft, which remains essentially straight, the spacing of the rolling elements remains constant.
In such devices a user applies both a vertical downward load and a transverse load to move the foot along the rollers causing different contact points of the rollers to interact with the bottom of the user's foot. These devices may also be used to roll the leg and other muscles. Under the nominal load of a person pushing their feet down onto the rolling elements, the rolling elements transfer the applied loads to the ground directly or via the mounting structure with minimal deformation to a rigid axial shaft.
Other devices included in this category are roller ball devices where rolling elements such as spheres are allowed to roll but are constrained to stay attached to one or more structural elements of the device such as the rigid axial shaft. Again, the spacing of the rolling elements along the axis of revolution is relatively constant.
Even in conventional foot rollers with non-rigid, flexible shafts such as a rope, the distance between the rolling elements (i.e., spheres) remains constant thereby greatly limiting the regions the user is able to massage. For example, the conventional foot roller may not be able to simultaneously massage the heel of the foot, and/or the two sides of the foot. Accordingly there is a need for massage devices that are able to roll, and provide constant contact to multiple surfaces of the foot.
A third group of foot rollers includes semi-deformable spherical, cylindrical or barrel shaped rollers which may be used either individually or as a group. The semi-deformable foot rollers may include foam or rubber features that interact with the bottom of the foot. In this group of foot rollers as the semi-deformable features are compressed, a transverse force causes the rollers to rotate along the bottom of the foot, and the transverse force causes the device to roll along the floor as the user applies a significant vertically downward load. Notably, these designs are prone to slippage as the device rolls.
Another part of the third group of foot rollers includes spherical semi-deformable devices. The spherical semi-deformable devices may include items like tennis balls, spheres with surface features (i.e. spikes), and/or peanut shaped devices. The spherical semi-deformable devices may be used to massage surfaces of the body. However conventional foot rollers from the third group are unable to massage both sides of the foot simultaneously. Additional products not used for massage from other industries include spherical semi-deformable devices such as dog toys, tennis balls and the like. However, none of devices may be used effectively for massaging the feet and other body parts.
Accordingly, there exists a need for a massage device that provides massage to various surfaces of a body part simultaneously.